Twenty of the women were overweight or obese based on their BMI (body mass index), which relates height to weight.

Another 20 had a normal BMI, but their body fat was greater than 30%, based on head-to-toe body scans using dual-energy X-ray absorptiometry (DEXA).

The researchers call these women "normal-weight obese" because of their high percentage of fat.

The remaining 20 women had a normal BMI and body fat less than 30%, based on the DEXA scans.

Measuring Inflammation

When researchers analyzed blood samples from the women, they found those who were overweight or obese had the highest levels of inflammatory chemicals, LDL ("bad") cholesterol, and triglycerides (a type of blood fat).

But the "normal-weight obese" women also had higher levels of inflammatory chemicals than those with both a normal BMI and lower body fat.

Based on the findings, the normal-weight women with high body fat "were in an early inflammatory state," the researchers write.

Body fat may release inflammatory chemicals, note researchers Antonino De Lorenzo, MD, and colleagues, who didn't test that theory in this study. De Lorenzo works at Rome's University of Tor Vergata.

Chronically high levels of inflammation have been associated with a host of health problems, including heart disease and arthritis.

Both groups of women with normal BMI had similar levels of cholesterol and other blood fats, regardless of their body fat.

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